I am not a lawyer, but from what I know it is not illegal to accept an offer and then decline it later before you have signed an agreement. For that matter, from my knowledge nothing generally would stop you from "quitting" the job on day 1, except you may create an upset employer.<p>You could simply go back and say something like:<p>"Hi Company X, as I am sure you realize I applied to multiple openings when looking to take my next position. And while I have been waiting to receive the contract from you I was contacted by another firm that showed interest and already received the contract from them. I greatly respect your time and efforts, but I feel this other offer is a better fit at this time for me. This has no reflection on your firm or offer, but I feel I might be a better fit with them, and I hope you understand. I hope we can work together in the future, thank you for all your hospitality"<p>I do think you have to be 100% up front about what you are doing, but companies get it, and this is a competitive market. You may burn a bridge here though at least with this company, so just be aware of that. In the end though, if you make it more about yourself and are up front, you likely won't create any major issues.<p>Just my 2 cents.